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Schwinger Pair Production
The Schwinger effect is a predicted physical phenomenon whereby matter is created by a strong electric field. It is also referred to as the Sauter–Schwinger effect, Schwinger mechanism, or Schwinger pair production. It is a prediction of quantum electrodynamics (QED) in which electron–positron pairs are spontaneously created in the presence of an electric field, thereby causing the decay of the electric field. The effect was originally proposed by Fritz Sauter in 1931 and further important work was carried out by Werner Heisenberg and Hans Heinrich Euler in 1936, though it was not until 1951 that Julian Schwinger gave a complete theoretical description. The Schwinger effect can be thought of as vacuum decay in the presence of an electric field. Although the notion of vacuum decay suggests that something is created out of nothing, physical conservation laws are nevertheless obeyed. To understand this, note that electrons and positrons are each other's antiparticles, with identi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Taylor Series
In mathematics, the Taylor series or Taylor expansion of a function is an infinite sum of terms that are expressed in terms of the function's derivatives at a single point. For most common functions, the function and the sum of its Taylor series are equal near this point. Taylor series are named after Brook Taylor, who introduced them in 1715. A Taylor series is also called a Maclaurin series when 0 is the point where the derivatives are considered, after Colin Maclaurin, who made extensive use of this special case of Taylor series in the 18th century. The partial sum formed by the first terms of a Taylor series is a polynomial of degree that is called the th Taylor polynomial of the function. Taylor polynomials are approximations of a function, which become generally more accurate as increases. Taylor's theorem gives quantitative estimates on the error introduced by the use of such approximations. If the Taylor series of a function is convergent, its sum is the limit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dirac Point
In physics, Dirac cones are features that occur in some electronic band structures that describe unusual electron transport properties of materials like graphene and topological insulators. In these materials, at energies near the Fermi level, the valence band and conduction band take the shape of the upper and lower halves of a conical surface, meeting at what are called Dirac points. Typical examples include graphene, topological insulators, bismuth antimony thin films and some other novel nanomaterials, in which the electronic energy and momentum have a linear dispersion relation such that the electronic band structure near the Fermi level takes the shape of an upper conical surface for the electrons and a lower conical surface for the holes. The two conical surfaces touch each other and form a zero-band gap semimetal. The name of Dirac cone comes from the Dirac equation that can describe relativistic particles in quantum mechanics, proposed by Paul Dirac. Isotropic Dira ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electron Hole
In physics, chemistry, and electronic engineering, an electron hole (often simply called a hole) is a quasiparticle denoting the lack of an electron at a position where one could exist in an atom or crystal structure, atomic lattice. Since in a normal atom or crystal lattice the negative charge of the electrons is balanced by the positive charge of the atomic nucleus, atomic nuclei, the absence of an electron leaves a net positive charge at the hole's location. Holes in a metal or semiconductor crystal lattice can move through the lattice as electrons can, and act similarly to electric charge, positively-charged particles. They play an important role in the operation of semiconductor devices such as transistors, diodes (including light-emitting diodes) and integrated circuits. If an electron is excited into a higher state it leaves a hole in its old state. This meaning is used in Auger electron spectroscopy (and other x-ray techniques), in computational chemistry, and to explai ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Andre Geim
Sir Andre Konstantin Geim (; born 21 October 1958; IPA1 pronunciation: ɑːndreɪ gaɪm) is a Russian-born Dutch–British physicist working in England in the School of Physics and Astronomy at the University of Manchester. Geim was awarded the 2010 Nobel Prize in Physics jointly with Konstantin Novoselov for his work on graphene. He is Regius Professor of Physics and Royal Society Research Professor at the National Graphene Institute. Geim was previously awarded an Ig Nobel Prize in 2000 for levitating a frog using its intrinsic magnetism. He is the first and only individual, as of 2025, to have received both Nobel and Ig Nobel prizes, for which he holds a Guinness World Record. Education Andre Geim was born to Konstantin Alekseyevich Geim and Nina Nikolayevna Bayer in Sochi, Russia, on 21 October 1958. Both his parents were engineers of German origin; Geim says his maternal great-grandmother was Jewish. His grandfather Nikolay N. Bayer (Mykola Baier in Ukrainian) was a notabl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
National Graphene Institute
The National Graphene Institute is a research institute and building at the University of Manchester, England, that is focused on the research of graphene. Construction of the building to house the institute started in 2013 and finished in 2015. Institute The creation of the institute, including the construction of the building, cost £61 million. Funded by the UK Government (£38 million) and the European Union's European Regional Development Fund (£23 million), the building is the national centre for graphene research in the UK. It provides facilities for industry and university academics to collaborate on graphene applications and the commercialisation of graphene. The building was opened on 20 March 2015 by the Chancellor of the Exchequer George Osborne. Building The five-storey glass-fronted building provides of research space. This includes of class 100 and class 1000 clean rooms, one of which occupies the entire lower ground floor (in order to minimi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Large Hadron Collider
The Large Hadron Collider (LHC) is the world's largest and highest-energy particle accelerator. It was built by the CERN, European Organization for Nuclear Research (CERN) between 1998 and 2008, in collaboration with over 10,000 scientists, and hundreds of universities and laboratories across more than 100 countries. It lies in a tunnel in circumference and as deep as beneath the France–Switzerland border near Geneva. The first collisions were achieved in 2010 at an energy of 3.5 tera-electronvolts (TeV) per beam, about four times the previous world record. The discovery of the Higgs boson at the LHC was announced in 2012. Between 2013 and 2015, the LHC was shut down and upgraded; after those upgrades it reached 6.5 TeV per beam (13.0 TeV total collision energy). At the end of 2018, it was shut down for maintenance and further upgrades, and reopened over three years later in April 2022. The collider has four crossing points where the accelerated particles ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MoEDAL Experiment
MoEDAL (Monopole and Exotics Detector at the LHC) is a particle physics experiment at the Large Hadron Collider (LHC). Experiment MoEDAL shares the cavern at Point 8 with LHCb, and its prime goal is to directly search for the magnetic monopole or dyon and other highly ionizing stable massive particles and pseudo-stable massive particles. To detect these particles, MoEDAL uses both nuclear track detectors and aluminium trapping volumes. There are approximately 10 m2 of nuclear track detectors placed around the interaction point. These suffer characteristic damage due to highly ionizing particles, such as magnetic monopoles or highly electrically charged particles. MoEDAL also has approximately 800 kg of aluminium bars placed around the interaction point, that can trap stable massive particles for later study. Passing these bars through a SQUID magnetometer yields a sensitive test for the presence of magnetic monopoles. MoEDAL is an international research collaboration whos ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magnetic Monopole
In particle physics, a magnetic monopole is a hypothetical particle that is an isolated magnet with only one magnetic pole (a north pole without a south pole or vice versa). A magnetic monopole would have a net north or south "magnetic charge". Modern interest in the concept stems from high-energy physics, particle theories, notably the grand unified theory, grand unified and superstring theory, superstring theories, which predict their existence. The known elementary particles that have electric charge are electric monopoles. Magnetism in bar magnets and electromagnets is not caused by magnetic monopoles, and indeed, there is no known experimental or observational evidence that magnetic monopoles exist. A magnetic monopole is not necessarily an elementary particle, and models for magnetic monopole production can include (but are not limited to) Spin (physics), spin-0 monopoles or spin-1 massive vector mesons. The term "magnetic monopole" only refers to the nature of the particle ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electromagnetic Dual
In physics, the electromagnetic dual concept is based on the idea that, in the static case, electromagnetism has two separate facets: electric fields and magnetic fields. Expressions in one of these will have a directly analogous, or dual, expression in the other. The reason for this can ultimately be traced to special relativity, where applying the Lorentz transformation to the electric field will transform it into a magnetic field. These are special cases of duality in mathematics. * The electric field () is the dual of the magnetic field (). * The electric displacement field () is the dual of the magnetic flux density (). * Faraday's law of induction is the dual of Ampère's circuital law. * Gauss's law for electric field is the dual of Gauss's law for magnetism. * The electric potential is the dual of the magnetic potential. * Permittivity is the dual of permeability. * Electrostriction is the dual of magnetostriction. * Piezoelectricity is the dual of piezomagnetism. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Extreme Light Infrastructure
The Extreme Light Infrastructure (ELI) is a research organization with the world's largest collection of high power-lasers. ELI operates several high-power, high-repetition-rate laser systems which enable the research of physical, chemical, materials, and medical sciences. ELI is part of the European Research Infrastructure Consortium (ERIC), where the official name and abbreviation came from: ELI ERIC. The organization consists of three complementary facilities, as well as collaborations with universities and research labs across the world. One of the facilities is ELI Beamlines, located outside of Prague in Dolní Břežany, Czech Republic; another facility, ELI ALPS (Attosecond Laser Pulse Source), is located in Szeged, Hungary; and the third facility is located in Măgurele, Romania (ELI Nuclear Physics, abbreviated as ELI NP). History From 2007 to 2010 ELI entered into a European-Commission-funded preparatory phase, comprising 40 laboratories from 13 countries. Gérard ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Schwinger Limit
In quantum electrodynamics (QED), the Schwinger limit is a scale above which the electromagnetic field is expected to become Nonlinear system, nonlinear. The limit was first derived in one of QED's earliest theoretical successes by Fritz Sauter in 1931 and discussed further by Werner Heisenberg and his student Hans Heinrich Euler. The limit, however, is commonly named in the literature for Julian Schwinger, who derived the leading nonlinear corrections to the fields and calculated the rate of Schwinger effect, electron–positron pair production in a strong electric field. The limit is typically reported as a maximum electric field or magnetic field before nonlinearity for the vacuum of :E_\text = \frac \simeq 1.32 \times 10^ \, \mathrm / \mathrm :B_\text = \frac \simeq 4.41 \times 10^ \, \mathrm , where ''m''e is the mass of the electron, ''c'' is the speed of light in vacuum, ''q''e is the elementary charge, and ''ħ'' is the reduced Planck constant. These are enormous field ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
